A conventional rotary rinser comprises a revolving body, bottle grippers disposed at an equal interval circumferentially around the outer periphery of the revolving body for receiving and inverting vessels as they are conveyed on a conveyor, a cleansing nozzle disposed on the revolving body at a location corresponding to each bottle gripper for injecting a cleansing fluid into a vessel which is held in its inverted position by the bottle gripper to cleanse the vessel, and a rotary valve which distributes an externally fed cleansing fluid to each cleansing nozzle (see, for example, Japanese Laid-Open Patent Application No. 11-277017).
A conventional rotary valve comprises a stationary valve member, and a rotary valve member which is disposed for rotation in sliding contact with the stationary valve member. The stationary valve member is formed with a supply passage which distributes the cleansing fluid fed from a pump while the rotary valve member is formed with a discharge passage which feeds the cleansing fluid into a piping connected to the cleansing nozzle. When the discharge passage of the rotary valve member communicates with the supply passage of the stationary passage at a given interval during the rotation of the rotary valve member, the cleansing fluid is fed through the piping into the cleansing nozzle to be injected into a vessel which is held gripped by one of the bottle grippers for cleansing this vessel.
When the rotary rinser constructed in the manner mentioned above is applied to an aseptic filling system which performs a filling of a sterilized liquid in an aseptic environment, the cleansing nozzle may be constructed as a double tube so that both the cleansing liquid and the air can be injected into the vessel. A cleansing nozzle having a double tube structure is used for purposes of substituting an aseptic air for the air within the vessel and for preventing an egress of the cleansing liquid from the vessel from being hindered by a narrowed opening of the vessel.
To feed the cleansing liquid and the air into the cleansing nozzle having the double tube structure as mentioned, the stationary valve member of the rotary valve is provided with supply passages for two kinds of fluids, the cleansing liquid and the air. The supply passages for such two kinds of fluids may be formed on a circumference of an equal radius as displaced from each other circumferentially or may be formed on circumferences having different radii. In either instance, sliding surfaces on the stationary valve member and on the rotary valve member into which the dual fluid supply passages open are located on a common plane.
In a conventional rotary valve which enables a dual fluid supply, distribution zones for dual fluids are located on a common plane and adjacent to each other, and this is likely to cause an interference between the fluids. In particular, when there exists a pressure difference between the dual fluids, a higher pressure fluid may permeate into a lower pressure fluid, and where a highly osmotic liquid such as sodium hydroxide is used, there exists a problem that it may be admixed with the other fluid. If sodium hydroxide finds its way into the air passage, there is a likelihood that it may be dried up in the air passage to be deposited on a wall surface as a scale to cause a nozzle plugging.
The present invention is made to overcome such problem, and has for its object the provision of a rotary rinser having a rotary valve which avoids the likelihood of fluids being brought into admixture if the rotary valve is used to distribute dual fluids.